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-rw-r--r--src/lib/libcrypto/ec/ec_mult.c673
1 files changed, 110 insertions, 563 deletions
diff --git a/src/lib/libcrypto/ec/ec_mult.c b/src/lib/libcrypto/ec/ec_mult.c
index 2ba173ef36..16822a73cf 100644
--- a/src/lib/libcrypto/ec/ec_mult.c
+++ b/src/lib/libcrypto/ec/ec_mult.c
@@ -1,9 +1,6 @@
1/* crypto/ec/ec_mult.c */ 1/* crypto/ec/ec_mult.c */
2/*
3 * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
4 */
5/* ==================================================================== 2/* ====================================================================
6 * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. 3 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
7 * 4 *
8 * Redistribution and use in source and binary forms, with or without 5 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions 6 * modification, are permitted provided that the following conditions
@@ -55,161 +52,41 @@
55 * Hudson (tjh@cryptsoft.com). 52 * Hudson (tjh@cryptsoft.com).
56 * 53 *
57 */ 54 */
58/* ====================================================================
59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
61 * and contributed to the OpenSSL project.
62 */
63
64#include <string.h>
65 55
66#include <openssl/err.h> 56#include <openssl/err.h>
67 57
68#include "ec_lcl.h" 58#include "ec_lcl.h"
69 59
70 60
71/* 61/* TODO: optional precomputation of multiples of the generator */
72 * This file implements the wNAF-based interleaving multi-exponentation method
73 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>);
74 * for multiplication with precomputation, we use wNAF splitting
75 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>).
76 */
77
78
79
80
81/* structure for precomputed multiples of the generator */
82typedef struct ec_pre_comp_st {
83 const EC_GROUP *group; /* parent EC_GROUP object */
84 size_t blocksize; /* block size for wNAF splitting */
85 size_t numblocks; /* max. number of blocks for which we have precomputation */
86 size_t w; /* window size */
87 EC_POINT **points; /* array with pre-calculated multiples of generator:
88 * 'num' pointers to EC_POINT objects followed by a NULL */
89 size_t num; /* numblocks * 2^(w-1) */
90 int references;
91} EC_PRE_COMP;
92
93/* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */
94static void *ec_pre_comp_dup(void *);
95static void ec_pre_comp_free(void *);
96static void ec_pre_comp_clear_free(void *);
97
98static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group)
99 {
100 EC_PRE_COMP *ret = NULL;
101
102 if (!group)
103 return NULL;
104
105 ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP));
106 if (!ret)
107 {
108 ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
109 return ret;
110 }
111 ret->group = group;
112 ret->blocksize = 8; /* default */
113 ret->numblocks = 0;
114 ret->w = 4; /* default */
115 ret->points = NULL;
116 ret->num = 0;
117 ret->references = 1;
118 return ret;
119 }
120
121static void *ec_pre_comp_dup(void *src_)
122 {
123 EC_PRE_COMP *src = src_;
124
125 /* no need to actually copy, these objects never change! */
126
127 CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP);
128
129 return src_;
130 }
131
132static void ec_pre_comp_free(void *pre_)
133 {
134 int i;
135 EC_PRE_COMP *pre = pre_;
136
137 if (!pre)
138 return;
139
140 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
141 if (i > 0)
142 return;
143
144 if (pre->points)
145 {
146 EC_POINT **p;
147
148 for (p = pre->points; *p != NULL; p++)
149 EC_POINT_free(*p);
150 OPENSSL_free(pre->points);
151 }
152 OPENSSL_free(pre);
153 }
154
155static void ec_pre_comp_clear_free(void *pre_)
156 {
157 int i;
158 EC_PRE_COMP *pre = pre_;
159
160 if (!pre)
161 return;
162
163 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
164 if (i > 0)
165 return;
166
167 if (pre->points)
168 {
169 EC_POINT **p;
170 62
171 for (p = pre->points; *p != NULL; p++)
172 EC_POINT_clear_free(*p);
173 OPENSSL_cleanse(pre->points, sizeof pre->points);
174 OPENSSL_free(pre->points);
175 }
176 OPENSSL_cleanse(pre, sizeof pre);
177 OPENSSL_free(pre);
178 }
179 63
180 64
65/*
66 * wNAF-based interleaving multi-exponentation method
67 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>)
68 */
181 69
182 70
183/* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. 71/* Determine the width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
184 * This is an array r[] of values that are either zero or odd with an 72 * This is an array r[] of values that are either zero or odd with an
185 * absolute value less than 2^w satisfying 73 * absolute value less than 2^w satisfying
186 * scalar = \sum_j r[j]*2^j 74 * scalar = \sum_j r[j]*2^j
187 * where at most one of any w+1 consecutive digits is non-zero 75 * where at most one of any w+1 consecutive digits is non-zero.
188 * with the exception that the most significant digit may be only
189 * w-1 zeros away from that next non-zero digit.
190 */ 76 */
191static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len) 77static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len, BN_CTX *ctx)
192 { 78 {
193 int window_val; 79 BIGNUM *c;
194 int ok = 0; 80 int ok = 0;
195 signed char *r = NULL; 81 signed char *r = NULL;
196 int sign = 1; 82 int sign = 1;
197 int bit, next_bit, mask; 83 int bit, next_bit, mask;
198 size_t len = 0, j; 84 size_t len = 0, j;
199 85
200 if (BN_is_zero(scalar)) 86 BN_CTX_start(ctx);
201 { 87 c = BN_CTX_get(ctx);
202 r = OPENSSL_malloc(1); 88 if (c == NULL) goto err;
203 if (!r) 89
204 {
205 ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
206 goto err;
207 }
208 r[0] = 0;
209 *ret_len = 1;
210 return r;
211 }
212
213 if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */ 90 if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
214 { 91 {
215 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); 92 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
@@ -219,90 +96,60 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
219 next_bit = bit << 1; /* at most 256 */ 96 next_bit = bit << 1; /* at most 256 */
220 mask = next_bit - 1; /* at most 255 */ 97 mask = next_bit - 1; /* at most 255 */
221 98
222 if (BN_is_negative(scalar)) 99 if (!BN_copy(c, scalar)) goto err;
100 if (c->neg)
223 { 101 {
224 sign = -1; 102 sign = -1;
103 c->neg = 0;
225 } 104 }
226 105
227 len = BN_num_bits(scalar); 106 len = BN_num_bits(c) + 1; /* wNAF may be one digit longer than binary representation */
228 r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer than binary representation 107 r = OPENSSL_malloc(len);
229 * (*ret_len will be set to the actual length, i.e. at most 108 if (r == NULL) goto err;
230 * BN_num_bits(scalar) + 1) */
231 if (r == NULL)
232 {
233 ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
234 goto err;
235 }
236 109
237 if (scalar->d == NULL || scalar->top == 0)
238 {
239 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
240 goto err;
241 }
242 window_val = scalar->d[0] & mask;
243 j = 0; 110 j = 0;
244 while ((window_val != 0) || (j + w + 1 < len)) /* if j+w+1 >= len, window_val will not increase */ 111 while (!BN_is_zero(c))
245 { 112 {
246 int digit = 0; 113 int u = 0;
247 114
248 /* 0 <= window_val <= 2^(w+1) */ 115 if (BN_is_odd(c))
249
250 if (window_val & 1)
251 { 116 {
252 /* 0 < window_val < 2^(w+1) */ 117 if (c->d == NULL || c->top == 0)
253
254 if (window_val & bit)
255 { 118 {
256 digit = window_val - next_bit; /* -2^w < digit < 0 */ 119 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
257 120 goto err;
258#if 1 /* modified wNAF */
259 if (j + w + 1 >= len)
260 {
261 /* special case for generating modified wNAFs:
262 * no new bits will be added into window_val,
263 * so using a positive digit here will decrease
264 * the total length of the representation */
265
266 digit = window_val & (mask >> 1); /* 0 < digit < 2^w */
267 }
268#endif
269 } 121 }
270 else 122 u = c->d[0] & mask;
123 if (u & bit)
271 { 124 {
272 digit = window_val; /* 0 < digit < 2^w */ 125 u -= next_bit;
126 /* u < 0 */
127 if (!BN_add_word(c, -u)) goto err;
273 } 128 }
274 129 else
275 if (digit <= -bit || digit >= bit || !(digit & 1))
276 { 130 {
277 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); 131 /* u > 0 */
278 goto err; 132 if (!BN_sub_word(c, u)) goto err;
279 } 133 }
280 134
281 window_val -= digit; 135 if (u <= -bit || u >= bit || !(u & 1) || c->neg)
282
283 /* now window_val is 0 or 2^(w+1) in standard wNAF generation;
284 * for modified window NAFs, it may also be 2^w
285 */
286 if (window_val != 0 && window_val != next_bit && window_val != bit)
287 { 136 {
288 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); 137 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
289 goto err; 138 goto err;
290 } 139 }
291 } 140 }
292 141
293 r[j++] = sign * digit; 142 r[j++] = sign * u;
294 143
295 window_val >>= 1; 144 if (BN_is_odd(c))
296 window_val += bit * BN_is_bit_set(scalar, j + w);
297
298 if (window_val > next_bit)
299 { 145 {
300 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); 146 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
301 goto err; 147 goto err;
302 } 148 }
149 if (!BN_rshift1(c, c)) goto err;
303 } 150 }
304 151
305 if (j > len + 1) 152 if (j > len)
306 { 153 {
307 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); 154 ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
308 goto err; 155 goto err;
@@ -311,6 +158,7 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
311 ok = 1; 158 ok = 1;
312 159
313 err: 160 err:
161 BN_CTX_end(ctx);
314 if (!ok) 162 if (!ok)
315 { 163 {
316 OPENSSL_free(r); 164 OPENSSL_free(r);
@@ -333,7 +181,7 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
333 (b) >= 300 ? 4 : \ 181 (b) >= 300 ? 4 : \
334 (b) >= 70 ? 3 : \ 182 (b) >= 70 ? 3 : \
335 (b) >= 20 ? 2 : \ 183 (b) >= 20 ? 2 : \
336 1)) 184 1))
337 185
338/* Compute 186/* Compute
339 * \sum scalars[i]*points[i], 187 * \sum scalars[i]*points[i],
@@ -341,15 +189,13 @@ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
341 * scalar*generator 189 * scalar*generator
342 * in the addition if scalar != NULL 190 * in the addition if scalar != NULL
343 */ 191 */
344int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, 192int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
345 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx) 193 size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
346 { 194 {
347 BN_CTX *new_ctx = NULL; 195 BN_CTX *new_ctx = NULL;
348 const EC_POINT *generator = NULL; 196 EC_POINT *generator = NULL;
349 EC_POINT *tmp = NULL; 197 EC_POINT *tmp = NULL;
350 size_t totalnum; 198 size_t totalnum;
351 size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */
352 size_t pre_points_per_block = 0;
353 size_t i, j; 199 size_t i, j;
354 int k; 200 int k;
355 int r_is_inverted = 0; 201 int r_is_inverted = 0;
@@ -361,15 +207,12 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
361 size_t num_val; 207 size_t num_val;
362 EC_POINT **val = NULL; /* precomputation */ 208 EC_POINT **val = NULL; /* precomputation */
363 EC_POINT **v; 209 EC_POINT **v;
364 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */ 210 EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */
365 const EC_PRE_COMP *pre_comp = NULL;
366 int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars,
367 * i.e. precomputation is not available */
368 int ret = 0; 211 int ret = 0;
369 212
370 if (group->meth != r->meth) 213 if (group->meth != r->meth)
371 { 214 {
372 ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); 215 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
373 return 0; 216 return 0;
374 } 217 }
375 218
@@ -378,226 +221,59 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
378 return EC_POINT_set_to_infinity(group, r); 221 return EC_POINT_set_to_infinity(group, r);
379 } 222 }
380 223
381 for (i = 0; i < num; i++)
382 {
383 if (group->meth != points[i]->meth)
384 {
385 ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS);
386 return 0;
387 }
388 }
389
390 if (ctx == NULL)
391 {
392 ctx = new_ctx = BN_CTX_new();
393 if (ctx == NULL)
394 goto err;
395 }
396
397 if (scalar != NULL) 224 if (scalar != NULL)
398 { 225 {
399 generator = EC_GROUP_get0_generator(group); 226 generator = EC_GROUP_get0_generator(group);
400 if (generator == NULL) 227 if (generator == NULL)
401 { 228 {
402 ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR); 229 ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
403 goto err; 230 return 0;
404 }
405
406 /* look if we can use precomputed multiples of generator */
407
408 pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
409
410 if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0))
411 {
412 blocksize = pre_comp->blocksize;
413
414 /* determine maximum number of blocks that wNAF splitting may yield
415 * (NB: maximum wNAF length is bit length plus one) */
416 numblocks = (BN_num_bits(scalar) / blocksize) + 1;
417
418 /* we cannot use more blocks than we have precomputation for */
419 if (numblocks > pre_comp->numblocks)
420 numblocks = pre_comp->numblocks;
421
422 pre_points_per_block = 1u << (pre_comp->w - 1);
423
424 /* check that pre_comp looks sane */
425 if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block))
426 {
427 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
428 goto err;
429 }
430 } 231 }
431 else 232 }
233
234 for (i = 0; i < num; i++)
235 {
236 if (group->meth != points[i]->meth)
432 { 237 {
433 /* can't use precomputation */ 238 ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
434 pre_comp = NULL; 239 return 0;
435 numblocks = 1;
436 num_scalar = 1; /* treat 'scalar' like 'num'-th element of 'scalars' */
437 } 240 }
438 } 241 }
439
440 totalnum = num + numblocks;
441 242
442 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); 243 totalnum = num + (scalar != NULL);
244
245 wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]);
443 wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); 246 wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]);
444 wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes space for pivot */ 247 wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]);
445 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); 248 if (wNAF != NULL)
446
447 if (!wsize || !wNAF_len || !wNAF || !val_sub)
448 { 249 {
449 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); 250 wNAF[0] = NULL; /* preliminary pivot */
450 goto err;
451 } 251 }
252 if (wsize == NULL || wNAF_len == NULL || wNAF == NULL) goto err;
452 253
453 wNAF[0] = NULL; /* preliminary pivot */ 254 /* num_val := total number of points to precompute */
454
455 /* num_val will be the total number of temporarily precomputed points */
456 num_val = 0; 255 num_val = 0;
457 256 for (i = 0; i < totalnum; i++)
458 for (i = 0; i < num + num_scalar; i++)
459 { 257 {
460 size_t bits; 258 size_t bits;
461 259
462 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); 260 bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
463 wsize[i] = EC_window_bits_for_scalar_size(bits); 261 wsize[i] = EC_window_bits_for_scalar_size(bits);
464 num_val += 1u << (wsize[i] - 1); 262 num_val += 1u << (wsize[i] - 1);
465 wNAF[i + 1] = NULL; /* make sure we always have a pivot */
466 wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]);
467 if (wNAF[i] == NULL)
468 goto err;
469 if (wNAF_len[i] > max_len)
470 max_len = wNAF_len[i];
471 }
472
473 if (numblocks)
474 {
475 /* we go here iff scalar != NULL */
476
477 if (pre_comp == NULL)
478 {
479 if (num_scalar != 1)
480 {
481 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
482 goto err;
483 }
484 /* we have already generated a wNAF for 'scalar' */
485 }
486 else
487 {
488 signed char *tmp_wNAF = NULL;
489 size_t tmp_len = 0;
490
491 if (num_scalar != 0)
492 {
493 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
494 goto err;
495 }
496
497 /* use the window size for which we have precomputation */
498 wsize[num] = pre_comp->w;
499 tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len);
500 if (!tmp_wNAF)
501 goto err;
502
503 if (tmp_len <= max_len)
504 {
505 /* One of the other wNAFs is at least as long
506 * as the wNAF belonging to the generator,
507 * so wNAF splitting will not buy us anything. */
508
509 numblocks = 1;
510 totalnum = num + 1; /* don't use wNAF splitting */
511 wNAF[num] = tmp_wNAF;
512 wNAF[num + 1] = NULL;
513 wNAF_len[num] = tmp_len;
514 if (tmp_len > max_len)
515 max_len = tmp_len;
516 /* pre_comp->points starts with the points that we need here: */
517 val_sub[num] = pre_comp->points;
518 }
519 else
520 {
521 /* don't include tmp_wNAF directly into wNAF array
522 * - use wNAF splitting and include the blocks */
523
524 signed char *pp;
525 EC_POINT **tmp_points;
526
527 if (tmp_len < numblocks * blocksize)
528 {
529 /* possibly we can do with fewer blocks than estimated */
530 numblocks = (tmp_len + blocksize - 1) / blocksize;
531 if (numblocks > pre_comp->numblocks)
532 {
533 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
534 goto err;
535 }
536 totalnum = num + numblocks;
537 }
538
539 /* split wNAF in 'numblocks' parts */
540 pp = tmp_wNAF;
541 tmp_points = pre_comp->points;
542
543 for (i = num; i < totalnum; i++)
544 {
545 if (i < totalnum - 1)
546 {
547 wNAF_len[i] = blocksize;
548 if (tmp_len < blocksize)
549 {
550 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
551 goto err;
552 }
553 tmp_len -= blocksize;
554 }
555 else
556 /* last block gets whatever is left
557 * (this could be more or less than 'blocksize'!) */
558 wNAF_len[i] = tmp_len;
559
560 wNAF[i + 1] = NULL;
561 wNAF[i] = OPENSSL_malloc(wNAF_len[i]);
562 if (wNAF[i] == NULL)
563 {
564 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
565 OPENSSL_free(tmp_wNAF);
566 goto err;
567 }
568 memcpy(wNAF[i], pp, wNAF_len[i]);
569 if (wNAF_len[i] > max_len)
570 max_len = wNAF_len[i];
571
572 if (*tmp_points == NULL)
573 {
574 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
575 OPENSSL_free(tmp_wNAF);
576 goto err;
577 }
578 val_sub[i] = tmp_points;
579 tmp_points += pre_points_per_block;
580 pp += blocksize;
581 }
582 OPENSSL_free(tmp_wNAF);
583 }
584 }
585 } 263 }
586 264
587 /* All points we precompute now go into a single array 'val'. 265 /* all precomputed points go into a single array 'val',
588 * 'val_sub[i]' is a pointer to the subarray for the i-th point, 266 * 'val_sub[i]' is a pointer to the subarray for the i-th point */
589 * or to a subarray of 'pre_comp->points' if we already have precomputation. */
590 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); 267 val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
591 if (val == NULL) 268 if (val == NULL) goto err;
592 {
593 ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
594 goto err;
595 }
596 val[num_val] = NULL; /* pivot element */ 269 val[num_val] = NULL; /* pivot element */
597 270
271 val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
272 if (val_sub == NULL) goto err;
273
598 /* allocate points for precomputation */ 274 /* allocate points for precomputation */
599 v = val; 275 v = val;
600 for (i = 0; i < num + num_scalar; i++) 276 for (i = 0; i < totalnum; i++)
601 { 277 {
602 val_sub[i] = v; 278 val_sub[i] = v;
603 for (j = 0; j < (1u << (wsize[i] - 1)); j++) 279 for (j = 0; j < (1u << (wsize[i] - 1)); j++)
@@ -609,12 +285,19 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
609 } 285 }
610 if (!(v == val + num_val)) 286 if (!(v == val + num_val))
611 { 287 {
612 ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); 288 ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
613 goto err; 289 goto err;
614 } 290 }
615 291
616 if (!(tmp = EC_POINT_new(group))) 292 if (ctx == NULL)
617 goto err; 293 {
294 ctx = new_ctx = BN_CTX_new();
295 if (ctx == NULL)
296 goto err;
297 }
298
299 tmp = EC_POINT_new(group);
300 if (tmp == NULL) goto err;
618 301
619 /* prepare precomputed values: 302 /* prepare precomputed values:
620 * val_sub[i][0] := points[i] 303 * val_sub[i][0] := points[i]
@@ -622,7 +305,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
622 * val_sub[i][2] := 5 * points[i] 305 * val_sub[i][2] := 5 * points[i]
623 * ... 306 * ...
624 */ 307 */
625 for (i = 0; i < num + num_scalar; i++) 308 for (i = 0; i < totalnum; i++)
626 { 309 {
627 if (i < num) 310 if (i < num)
628 { 311 {
@@ -641,11 +324,16 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
641 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err; 324 if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
642 } 325 }
643 } 326 }
327
328 wNAF[i + 1] = NULL; /* make sure we always have a pivot */
329 wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i], ctx);
330 if (wNAF[i] == NULL) goto err;
331 if (wNAF_len[i] > max_len)
332 max_len = wNAF_len[i];
644 } 333 }
645 334
646#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ 335#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
647 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) 336 if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err;
648 goto err;
649#endif 337#endif
650 338
651 r_is_at_infinity = 1; 339 r_is_at_infinity = 1;
@@ -741,198 +429,57 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
741 } 429 }
742 430
743 431
744/* ec_wNAF_precompute_mult() 432int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar, const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx)
745 * creates an EC_PRE_COMP object with preprecomputed multiples of the generator 433 {
746 * for use with wNAF splitting as implemented in ec_wNAF_mul(). 434 const EC_POINT *points[1];
747 * 435 const BIGNUM *scalars[1];
748 * 'pre_comp->points' is an array of multiples of the generator 436
749 * of the following form: 437 points[0] = point;
750 * points[0] = generator; 438 scalars[0] = p_scalar;
751 * points[1] = 3 * generator; 439
752 * ... 440 return EC_POINTs_mul(group, r, g_scalar, (point != NULL && p_scalar != NULL), points, scalars, ctx);
753 * points[2^(w-1)-1] = (2^(w-1)-1) * generator; 441 }
754 * points[2^(w-1)] = 2^blocksize * generator; 442
755 * points[2^(w-1)+1] = 3 * 2^blocksize * generator; 443
756 * ... 444int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
757 * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) * generator
758 * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) * generator
759 * ...
760 * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) * generator
761 * points[2^(w-1)*numblocks] = NULL
762 */
763int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
764 { 445 {
765 const EC_POINT *generator; 446 const EC_POINT *generator;
766 EC_POINT *tmp_point = NULL, *base = NULL, **var;
767 BN_CTX *new_ctx = NULL; 447 BN_CTX *new_ctx = NULL;
768 BIGNUM *order; 448 BIGNUM *order;
769 size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num;
770 EC_POINT **points = NULL;
771 EC_PRE_COMP *pre_comp;
772 int ret = 0; 449 int ret = 0;
773 450
774 /* if there is an old EC_PRE_COMP object, throw it away */
775 EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
776
777 if ((pre_comp = ec_pre_comp_new(group)) == NULL)
778 return 0;
779
780 generator = EC_GROUP_get0_generator(group); 451 generator = EC_GROUP_get0_generator(group);
781 if (generator == NULL) 452 if (generator == NULL)
782 { 453 {
783 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR); 454 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR);
784 goto err; 455 return 0;
785 } 456 }
786 457
787 if (ctx == NULL) 458 if (ctx == NULL)
788 { 459 {
789 ctx = new_ctx = BN_CTX_new(); 460 ctx = new_ctx = BN_CTX_new();
790 if (ctx == NULL) 461 if (ctx == NULL)
791 goto err; 462 return 0;
792 } 463 }
793 464
794 BN_CTX_start(ctx); 465 BN_CTX_start(ctx);
795 order = BN_CTX_get(ctx); 466 order = BN_CTX_get(ctx);
796 if (order == NULL) goto err; 467 if (order == NULL) goto err;
797 468
798 if (!EC_GROUP_get_order(group, order, ctx)) goto err; 469 if (!EC_GROUP_get_order(group, order, ctx)) return 0;
799 if (BN_is_zero(order)) 470 if (BN_is_zero(order))
800 { 471 {
801 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER); 472 ECerr(EC_F_EC_GROUP_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER);
802 goto err; 473 goto err;
803 } 474 }
804 475
805 bits = BN_num_bits(order); 476 /* TODO */
806 /* The following parameters mean we precompute (approximately)
807 * one point per bit.
808 *
809 * TBD: The combination 8, 4 is perfect for 160 bits; for other
810 * bit lengths, other parameter combinations might provide better
811 * efficiency.
812 */
813 blocksize = 8;
814 w = 4;
815 if (EC_window_bits_for_scalar_size(bits) > w)
816 {
817 /* let's not make the window too small ... */
818 w = EC_window_bits_for_scalar_size(bits);
819 }
820
821 numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks to use for wNAF splitting */
822
823 pre_points_per_block = 1u << (w - 1);
824 num = pre_points_per_block * numblocks; /* number of points to compute and store */
825
826 points = OPENSSL_malloc(sizeof (EC_POINT*)*(num + 1));
827 if (!points)
828 {
829 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
830 goto err;
831 }
832
833 var = points;
834 var[num] = NULL; /* pivot */
835 for (i = 0; i < num; i++)
836 {
837 if ((var[i] = EC_POINT_new(group)) == NULL)
838 {
839 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
840 goto err;
841 }
842 }
843
844 if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group)))
845 {
846 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
847 goto err;
848 }
849
850 if (!EC_POINT_copy(base, generator))
851 goto err;
852
853 /* do the precomputation */
854 for (i = 0; i < numblocks; i++)
855 {
856 size_t j;
857
858 if (!EC_POINT_dbl(group, tmp_point, base, ctx))
859 goto err;
860
861 if (!EC_POINT_copy(*var++, base))
862 goto err;
863
864 for (j = 1; j < pre_points_per_block; j++, var++)
865 {
866 /* calculate odd multiples of the current base point */
867 if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx))
868 goto err;
869 }
870
871 if (i < numblocks - 1)
872 {
873 /* get the next base (multiply current one by 2^blocksize) */
874 size_t k;
875
876 if (blocksize <= 2)
877 {
878 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERNAL_ERROR);
879 goto err;
880 }
881
882 if (!EC_POINT_dbl(group, base, tmp_point, ctx))
883 goto err;
884 for (k = 2; k < blocksize; k++)
885 {
886 if (!EC_POINT_dbl(group,base,base,ctx))
887 goto err;
888 }
889 }
890 }
891
892 if (!EC_POINTs_make_affine(group, num, points, ctx))
893 goto err;
894
895 pre_comp->group = group;
896 pre_comp->blocksize = blocksize;
897 pre_comp->numblocks = numblocks;
898 pre_comp->w = w;
899 pre_comp->points = points;
900 points = NULL;
901 pre_comp->num = num;
902
903 if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp,
904 ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free))
905 goto err;
906 pre_comp = NULL;
907 477
908 ret = 1; 478 ret = 1;
479
909 err: 480 err:
910 if (ctx != NULL) 481 BN_CTX_end(ctx);
911 BN_CTX_end(ctx);
912 if (new_ctx != NULL) 482 if (new_ctx != NULL)
913 BN_CTX_free(new_ctx); 483 BN_CTX_free(new_ctx);
914 if (pre_comp)
915 ec_pre_comp_free(pre_comp);
916 if (points)
917 {
918 EC_POINT **p;
919
920 for (p = points; *p != NULL; p++)
921 EC_POINT_free(*p);
922 OPENSSL_free(points);
923 }
924 if (tmp_point)
925 EC_POINT_free(tmp_point);
926 if (base)
927 EC_POINT_free(base);
928 return ret; 484 return ret;
929 } 485 }
930
931
932int ec_wNAF_have_precompute_mult(const EC_GROUP *group)
933 {
934 if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL)
935 return 1;
936 else
937 return 0;
938 }
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-04-27 05:59:25 +0000